Combinatorial X-ray diffractor

ABSTRACT

A combinatorial X-ray diffractor, particularly a combinatorial X-ray diffractor which can measure one row of samples among a plurality of samples arranged into a matrix simultaneously by X-ray diffraction. For the purpose of high throughput screening, a plurality of samples ( 10 ) are arranged into a row X 1 , a row X 2 , a row X 3 , and a row X 4  on a sample stage and samples in each row are measured simultaneously by X-ray diffraction, measured data are processed by an information processor ( 20 ), information data useful for the evaluation of thin film material are automatically extracted and arranged and the extracted and arranged information data are displayed on a display apparatus ( 27 ).

TECHNICAL FIELD

The present invention relates to a combinatorial X-ray diffractionapparatus, and, more specifically, to an X-ray diffraction apparatus forcombinatorial evaluation of epitaxial thin film, which apparatus cansimultaneously measure, through X-ray diffraction, samples in onecolumn, among a plurality of samples disposed in a matrix pattern.

BACKGROUND ART

When a new functional material is produced through mixing variouselements (elements/molecules), determining an optimal composition andmixing proportions is difficult. In particular, when the number ofcomponent elements and the molecular weight of a material to be producedare increased, a conventional approach; i.e., a process of producingdifferent materials on a material-by-material basis while graduallychanging the production conditions and investigating the properties ofthe materials on a material-by-material basis, requires an astronomicalamount of time and is therefore difficult to employ.

In order to solve the above-described problem, an approach calledcombinatorial chemistry has been proposed. Under this approach, a regionin which production of a target material is highly probable is screenedsystematically. This approach drastically improves synthesis efficiencyof new organic substances such as polypeptides.

FIG. 1 illustrates the principle of combinatorial chemistry. A methodcalled parallel synthesis will be described briefly.

First, as shown in FIG. 1(a), a large number of reaction chambers areprepared. Component materials are placed in the reaction chambers suchthat composition and mixing proportions vary in the row and columndirections, respectively. Upon simultaneous reaction, as shown in FIG.1(b), a large number of different materials resulting from systematicalcombination of different compositions and proportions are obtainedconcurrently. That is, when this approach is used, materials researchcan be performed quite efficiently as compared with the case in which amaterial corresponding to each different combination is produced throughreaction. Further, since a large number of combinations can be testedunder identical conditions, the production conditions can be madeuniform among the different materials, which is extremely advantageous.

If this approach is applied to fabrication of thin film, it becomespossible to fabricate on a single substrate a thin film of a material inwhich the proportions of two elements are changed gradually.Specifically, three targets of, for example, ZnO, Co_(0.1)Zn_(0.9)O, andFe_(0.1)Zn_(0.9)O are prepared, and deposition is performed while theamounts of deposition are controlled by use of a mask. Thus, thin filmsof Fe_(x)Co_(y)Zn_(1−x−y)O are formed on a single substrate such thatthe compositional proportions x and y vary among the thin films.Further, the above-described method enables production of a superlatticein which the stacking cycles of respective compounds are varied.

A secondary important point is efficient performance of evaluation whichis performed for finding prospective combinations by use of thethus-formed thin films having different compositions and/or stackingcycles.

DISCLOSURE OF THE INVENTION

A very important step is to evaluate the crystalline structures andlattice constants of thin films which have been fabricated in the manneras described above and which have different compositions and/or stackingcycles. However, a conventional evaluation method performed by use of anX-ray diffraction apparatus premises that a material to be evaluated hasa uniform structure in a region irradiated with an X-ray. Therefore,when the composition and structure of the material vary among narrowregions, radiation of an X-ray beam must be restricted such that theX-ray beam is radiated only to a region of uniform structure.

Further, in order to evaluate all the fabricated films, measurement mustbe repeated a large number of times, which requires a very long time.Therefore, even if thin films of different compositions can beefficiently fabricated concurrently, evaluating the fabricated filmsrequires a long time. Therefore, overall efficiency is not high.

Therefore, an X-ray diffraction apparatus capable of quickly evaluatingan object whose structure varies depending on position is demanded.

In view of the forgoing, an object of the present invention is toprovide a combinatorial X-ray diffraction apparatus which canefficiently use X-rays from an X-ray source and which can quicklyperform accurate measurement and evaluation of a large number ofepitaxial thin films disposed at different positions.

To achieve the above object, the present invention provides thefollowing:

[1] A combinatorial x-ray diffraction apparatus comprising: an X-raysource for radiating X-rays from a point-shaped focal point; a curvedmonochromator which spectrally reflects the X-rays radiated from theX-ray source; a slit disposed for restricting radiation of the reflectedX-rays to a measurement area; a knife-edge slit disposed for selecting adesired portion of the X-rays having passed through the slit; a holderfor holding a combinatorial epitaxial thin film to be irradiated withthe X-rays restricted by the knife-edge slit; a two-dimensional detectorfor receiving diffraction X-rays reflected from the epitaxial thin filmheld by the holder; a goniometer having a ω-axis shaft and a 2θ-axisshaft, the holder being mounted on the ω-axis shaft, and thetwo-dimensional detector being mounted on the 2θ-axis shaft; a driveunit for moving the position at which the X-rays impinge the epitaxialthin film; an information processing apparatus for fetching output datafrom the two-dimensional detector and processing the data; and a displayunit for displaying the result of processing performed in theinformation processing apparatus.

[2] A combinatorial X-ray diffraction apparatus comprising: an X-raysource for radiating X-rays from a line-shaped focal point; a curvedmonochromator which reflects the X-rays radiated from the X-ray source,while converting the X-rays to monochromic rays; a slit disposed forrestricting radiation of the reflected X-rays to a measurement area; aknife-edge slit disposed for selecting a desired portion of the X-rayshaving passed through the slit; a holder for holding a combinatorialepitaxial thin film to be irradiated with the X-rays restricted by theknife-edge slit; a Soller slit which affects the X-rays having passedthrough the knife-edge slit; a two-dimensional detector for receivingdiffraction X-rays reflected from the epitaxial thin film held by theholder; a goniometer having a ω-axis shaft and a 2θ-axis shaft, theholder being mounted on the ω-axis shaft, and the two-dimensionaldetector being mounted on the 2θ-axis shaft; a drive unit for moving theposition at which the X-rays impinge the epitaxial thin film; aninformation processing apparatus for fetching output data from thetwo-dimensional detector and processing the data; and a display unit fordisplaying the result of processing performed in the informationprocessing apparatus.

[3] A combinatorial X-ray diffraction apparatus as described in or [1]or [2] above, further characterized in that the combinatorial epitaxialthin film includes a plurality of epitaxial thin films disposed in acolumn direction.

[4] A combinatorial X-ray diffraction apparatus as described in any oneof [1] to [3] above, further characterized in that the apparatus is setsuch that, among cells of a plurality of epitaxial thin films formed ina matrix pattern in accordance with a combinatorial method, at least twocells forming a cell column simultaneously satisfy diffractionconditions.

[5] A combinatorial X-ray diffraction apparatus as described in any oneof [1] to [4] above, further characterized in that the two-dimensionaldetector is disposed such that the two-dimensional detector can receivesimultaneously X-rays from at least two cells forming a cell column,among cells of a plurality of epitaxial thin films formed in a matrixpattern in accordance with a combinatorial method.

[6] A combinatorial X-ray diffraction apparatus as described in any oneof [1] to [5] above, further characterized in that the apparatus is setsuch that, among cells of a plurality of epitaxial thin films formed ina matrix pattern in accordance with a combinatorial method, cell columnseach including at least two cells sequentially satisfy diffractionconditions, and in that the two-dimensional detector is disposed suchthat the two-dimensional detector can receive diffraction X-raysdiffracted at the cell columns sequentially.

[7] A combinatorial X-ray diffraction apparatus as described in any oneof [1] to [6] above, further characterized in that the spatialdistribution of X-ray intensity and the spatial distribution ofsensitivity of the two-dimensional detector are normalized; and for eachpixel or each block of pixels of diffracted X-rays collectedtwo-dimensionally, X-ray intensity correction is performed according tothe position thereof.

[8] A combinatorial X-ray diffraction apparatus as described in any oneof [1] to [7] above, further characterized in that diffraction X-raysdiffracted at a cell column including at least two cells, among cells ofa plurality of epitaxial thin films formed in a matrix pattern inaccordance with a combinatorial method, are received simultaneously bythe two-dimensional detector; positions of each cell in a direction ofdiffraction angle θ and in a direction perpendicular thereto aremeasured; and diffraction X-ray intensities of pixels of thetwo-dimensional detector corresponding to each cell of the epitaxialthin film are integrated in order to individually obtain the intensityof diffraction X-rays from each cell.

[9] A combinatorial X-ray diffraction apparatus as described in any oneof [1] to [8] above, further characterized in that from diffractionX-rays diffracted at a cell column including at least two cells, amongcells of a plurality of epitaxial thin films formed in a matrix patternin accordance with a combinatorial method, the intensity of adiffraction X-ray from each cell is separated and related with angleinformation representing a diffraction angle θ, through movement of theepitaxial thin film on the goniometer and the movement of thetwo-dimensional detector, within a desired angle range.

[10] A combinatorial X-ray diffraction apparatus as described in [8] or[9] above, further characterized in that diffraction X-ray data obtainedwith respect to each cell are stored or displayed as they are or afterbeing subjected to X-ray intensity correction or background eliminationcorrection; or a peak intensity, a peak position, and half-value widthare calculated from the data and are stored or displayed.

[11] A combinatorial X-ray diffraction apparatus as described in [10]above, further characterized in that, in addition to data processing,storage, or display, the diffraction X-ray data obtained with respect toeach cell are subjected to additional data processing, storage, display,or data analysis which are performed under comparison with data withrespect to each cell column or the combinatorial cell matrix.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1(a) and 1(b) are diagrams showing the principle of combinatorialchemistry;

FIG. 2 is a schematic perspective view of an X-ray diffraction apparatusaccording to an embodiment of the present invention;

FIG. 3 is a view showing the layout of components of the X-raydiffraction apparatus according to the embodiment of the presentinvention;

FIG. 4 is a schematic plan view of the X-ray diffraction apparatusaccording to the embodiment of the present invention;

FIG. 5 is a diagram used for explanation of movement of a sample stageof the X-ray diffraction apparatus according to the embodiment of thepresent invention;

FIGS. 6(a) and 6(b) are diagrams showing a process in which X-rays areradiated onto a combinatorial sample in the X-ray diffraction apparatusaccording to the embodiment of the present invention;

FIG. 7 is an explanatory view showing a data processing method forsample evaluation performed by the X-ray diffraction apparatus accordingto the embodiment of the present invention;

FIG. 8 shows a first reflective image of a superlattice (SrTiO₃/BaTiO₃)obtained in a first test example of the present invention;

FIGS. 9(a) to 9(c) are graphs showing profiles of X-ray intensitymeasured along lines (a) to (c) in FIG. 8;

FIG. 10 shows a second reflective image of a superlattice(SrTiO₃/BaTiO₃) obtained in the first test example of the presentinvention;

FIGS. 11(a) to 11(c) are graphs showing profiles of X-ray intensitymeasured along lines (a) to (c) in FIG. 10;

FIG. 12 shows a first (100) reflective image obtained in the first testexample of the present invention;

FIGS. 13(a) to 13(c) are graphs showing profiles of X-ray intensitymeasured along lines (a) to (c) in FIG. 12;

FIG. 14 shows a second (100) reflective image obtained in the first testexample of the present invention;

FIGS. 15(a) to 15(c) are graphs showing profiles of X-ray intensitymeasured along lines (a) to (c) in FIG. 14;

FIG. 16 shows an image obtained through photographing the same sample asin FIG. 14 but an inverted state;

FIG. 17 shows a ZnO (002) reflective image obtained in a second testexample of the present invention;

FIGS. 18(a) and 18(b) are graphs showing profiles of X-ray intensitymeasured along lines (a) and (b) in FIG. 17;

FIG. 19 shows a (006) reflective image of a sapphire substrate obtainedin a third test example of the present invention;

FIG. 20 is a graph showing a profile of X-ray intensity measured alongline A—A in FIG. 19;

FIG. 21 is a graph showing profiles obtained through measurement inwhich the thickness of ZnO film was measured on a cell-by-cell basis;

FIG. 22 is a schematic view of an X-ray diffraction apparatus accordingto the present invention in which a point light source is used; and

FIG. 23 is a schematic view of an X-ray diffraction apparatus accordingto the present invention in which a line light source is used.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will next be described in detail.

FIG. 2 is a schematic perspective view of an X-ray diffraction apparatusaccording to an embodiment of the present invention; FIG. 3 is a viewshowing the layout of components of the X-ray diffraction apparatus;FIG. 4 is a schematic plan view of the X-ray diffraction apparatus; andFIG. 5 is a diagram used for explanation of movement of a sample stageof the X-ray diffraction apparatus.

In these drawings, reference numeral 1 denotes an X-ray source forradiating divergent X-rays; 2 denotes a monochromator having a curvedcrystal; 3 denotes a slit for restricting an X-ray radiation area; and 5denotes a (ω/2θ) goniometer. The goniometer 5 has a sample rotationshaft 5A and a detector shaft 5B. A sample stage 9 is mounted on thesample rotation shaft 5A, and a plurality of samples 4 are placed on thesample stage 9. A 2θ counter arm 5C is fixed to the detector shaft 5B,and a two-dimensional detector 7 is disposed at the distal end portionof the counter arm 5C. The samples (epitaxial thin film) 4 are disposedin a matrix pattern. Reference numeral 6 denotes a knife-edge slitdisposed such that X-rays are radiated onto only samples 4 in a singlecolumn, among the samples 4 disposed in a matrix pattern. Thetwo-dimensional detector 7 is an imaging plate (IP) or CCD camera.Reference numeral 8 denotes a sample position setting unit.

As shown in FIG. 5, the sample stage 9 of the X-ray diffractionapparatus is moved in relation to 5 axes in total; i.e., X and Y axesfor horizontal translation, a Z axis for translation in the thicknessdirection of the sample, a φ axis for rotation in the sample plane, andan X axis for tilting.

In the present invention, since the two-dimensional detector 7 and themonochromator 2 formed of a curved crystal are combined, X-raydiffraction can be performed over an angular range of a few degrees.Therefore, the plurality of samples arranged in a matrix pattern can bemeasured simultaneously.

Next, operation of the X-ray diffraction apparatus of the presentinvention will be described.

In order to utilize divergent X-rays radiated from the X-ray source 1most efficiently, the X-rays are converted to monochromic rays by use ofthe monochromator 2 formed of a Johansson-type curved crystal. In thiscase, the divergence angle can be increased to about 4°. Although thesize of the X-ray beam measured at the sample 4 position variesdepending on the X-ray focus size and the machining accuracy of theJohansson-type curved crystal, the size of the X-ray beam can be reducedto about 0.1 to 0.2 mm. In place of the Johansson-type curved crystal, aJohann-type curved crystal may be used.

The beam size can be reduced further by the knife-edge slit 6 disposedimmediately before the sample 4. The knife-edge slit 6 reduces theinfluence of a background formed by scattered light. X-rays diffractedby the samples 4 in a certain column impinge on the two-dimensionaldetector (imaging plate) 7 with respective scattering angles. Thus, theplurality of samples 4 in the certain column are detected.

FIG. 6(a) shows a plurality of samples 10 disposed in a matrix pattern.As shown in FIG. 6(b), at first, only a plurality of samples 11 in thefirst column among the plurality of samples 10 disposed in a matrixpattern are irradiated with X-rays for simultaneous X-ray diffractionanalysis.

FIG. 7 is an explanatory view showing a data processing method forsample evaluation performed by the X-ray diffraction apparatus accordingto the embodiment of the present invention.

In FIG. 7, reference numeral 10 denotes a plurality of samples disposedin a matrix pattern; 11 denotes a plurality of samples in the firstcolumn (a plurality of samples in column X₁); 12 denotes a plurality ofsamples in column X₂; 13 denotes a plurality of samples in column X₃; 14denotes a plurality of samples in column X₄; 15 denotes atwo-dimensional detector; 20 denotes an information processingapparatus; 21 denotes a CPU (central processing unit); 22, 25, and 26each denote an interface (I/F); 23 denotes a memory unit; 24 denotes anedit unit; and 27 denotes a display unit. The memory unit 23 is composedof ROM in which a program is stored in advance and RAM in whichlater-produced data are stored.

As described above, among the plurality of samples 10 disposed in amatrix pattern, a plurality of samples in one column are simultaneouslysubjected to X-ray diffraction analysis. Specifically, at time t₁, theplurality of samples 11 in column X₁ simultaneously undergo X-raydiffraction analysis, as shown in FIG. 7(a). Subsequently, at time t₂,the sample stage 9 is moved in order to change the X-ray radiationposition to column X₂, as shown in FIG. 7(b). As a result, the pluralityof samples 12 in column X₂ simultaneously undergo X-ray diffractionanalysis. Similarly, at time t₃, the plurality of samples 13 in columnX₃ simultaneously undergo X-ray diffraction analysis, as shown in FIG.7(c). Next, at time t₄, the plurality of samples 14 in column X₄simultaneously undergo X-ray diffraction analysis, as shown in FIG.7(d). Thus, all the samples are measured by the two-dimensional detector15.

Data from the two-dimensional detector 15 which represent measurementinformation collected for each column of samples are fetched by theinformation processing apparatus 20. By means of integrated controlperformed by the CPU (central processing unit) 21, the data from thetwo-dimensional detector 15 are fetched via the interface 22 and storedin the memory unit 23 in a time series fashion. The thus-stored data areedited by the edit unit 24 and then output to the display unit 27 viathe interface 26 to be displayed in a time series fashion.

Further, the goniometer 5 is controlled via the interface 25.

Next, measurement of samples by the X-ray diffraction apparatus will bedescribed.

(1) First, the position and orientation of the samples 4 placed on thesample stage 9 are set (manually or automatically) by means of thesample position setting unit 8 and the moving mechanism of the samplestage 9, and the position of the two-dimensional detector 15 is setaccurately through rotation of the detector shaft 5B (step S1).

(2) Subsequently, as shown in FIG. 7(a), the samples in column X₁ areirradiated with X-rays such that X-ray diffraction occurs, the X-raydiffraction is measured by the two-dimensional detector 15, andmeasurement data are fetched by the information processing apparatus 20(step S2).

(3) Subsequently, the sample stage 9 is moved in order to change theX-ray radiation position to the next sample position; e.g., to columnX₂, as shown in FIG. 7(b) (step S3).

(4) Subsequently, the samples in column X₂ are irradiated with X-rayssuch that X-ray diffraction occurs, the X-ray diffraction is measured bythe two-dimensional detector 15, and measurement data are fetched by theinformation processing apparatus 20 (step S4).

(5) While the X-ray radiation position is changed to the sample columnshown in FIG. 7(c) and then to the sample column shown in FIG. 7(d), theabove-described operation; i.e., X-ray irradiation for causing X-raydiffraction, measurement by the two-dimensional detector 15, andfetching of measurement data by the information processing apparatus 20,is repeated (step S5).

(6) In the above-described measurement, photographing is performedwithin a limited angle θ (typically 3 to 4°). When the photographingarea is to be increased, the X-ray diffraction angle 2θ and the samplerotation angle ω are changed, through drive of the detector shaft 5B andthe sample shaft 5A, to thereby enable X-ray diffraction analysis ofsamples in a wider area.

The combinatorial X-ray diffraction apparatus can be configured to havethe following functions.

(1) In general, X-rays are radiated onto samples with non-uniformintensity. Therefore, the information processing apparatus 20 ispreferably configured to have a function of normalizing the X-rayintensity distribution and for calculating a true X-ray diffractionintensity corresponding to each pixel. Specifically, the spatialdistribution of X-ray intensity and the spatial distribution ofsensitivity of the two-dimensional detector 15 are normalized; and foreach pixel or each block of pixels of diffracted X-rays collectedtwo-dimensionally, X-ray intensity correction is performed according tothe position thereof.

(2) The information processing apparatus 20 is preferably configured tohave a function of previously performing correction on the relationshipbetween the position of each pixel and a corresponding diffractionangle, for each position of the ω/2θ goniometer 5. Effective methods forthis correction include a method in which a peak position of thesubstrate is used as a reference, and a method in which calibration isperformed while samples are inverted.

(3) The information processing apparatus 20 is preferably configured tohave a function of integrating X-ray intensities of arbitrary pixelslocated along a direction perpendicular to θ, in order to obtain adiffraction intensity with respect to a single unit of samples.

(4) The information processing apparatus 20 is preferably configured tohave a function of performing measurement within two or more angularregions which have previously been set in the memory unit (ROM) 23 bymeans of a program, performing the corrections described in (1) to (3)above, and storing in the memory unit (ROM) 23 data of a profilerepresenting the X-ray diffraction intensity of each pixel.

(5) The information processing apparatus 20 is preferably configured tohave a function of automatically calculating a peak position, a peakintensity, and a half-value width from the profile data obtained in (4)above and for storing these values in the memory unit (ROM) 23.

Next, specific test examples will be described.

Measurement was performed under the following conditions: (1) X-rays:CuKαl, 40 kV-30 mA, 0.1 mmx 0.1 mm focus; (2) monochromator: a quartz(101) 3°, off, Johann type, convergence to 2°; (3) distance between theX-ray source and the monochromator: 240 mm; distance between themonochromator and the sample: 153 mm; camera length: 300 mm; (4)exposure time: rocking curve: 30 sec; (5) detector: blue IP (imagingplate) (Rigaku/DS3), 50 μm reading pitch.

FIG. 8 shows a first reflective image of a superlattice (SrTiO₃/BaTiO₃)obtained in a first test example of the present invention; FIGS. 9(a) to9(c) are graphs showing profiles of X-ray intensity measured along lines(a) to (c) in FIG. 8; FIG. 10 shows a second reflective image of asuperlattice (SrTiO₃/BaTiO₃) obtained in the first test example of thepresent invention; and FIGS. 11(a) to 11(c) are graphs showing profilesof X-ray intensity measured along lines (a) to (c) in FIG. 10.

FIGS. 8-9(c) and FIGS. 10-11(c) show rocking curves in the vicinity of200 reflection. The measurement was performed while the measurementposition was changed in the X direction in FIG. 6.

FIGS. 12-13(c) and FIGS. 14-15(c) show 100 reflection images and theirprofiles obtained in the first test example of the present invention.The measurement was performed while the measurement position waschanged. FIG. 16 shows an image obtained through photographing thesample in an inverted state.

The images of the rocking curves show that the refraction lines areskewed due to twist (orientation change) of the substrate crystal. Asshown in FIG. 16, the direction of screw is the same even when thesample is photographed in an inverted state, which demonstrates that thescrew stems from twist of the crystal. For confirmation, a mapmeasurement was performed while the X-ray radiation field on the samplewas narrowed. The screw with respect to the vertical direction isgreater than 0.2°.

In either test result, the position at which the peak of thesuperlattice appears varies depending on the cycle of the superlattice.The position of the peak varies depending on position even in the sameregion. The profile is displayed by use of an integral value of 5adjacent pixels. The selected portion was substantially the center ofthe region, and stepped portions were avoided.

Next will be described the case of a stripe-shaped ZnO thin film formedon a sapphire substrate in a second test example of the presentinvention.

FIG. 17 shows a ZnO (002) reflective image obtained in the second testexample of the present invention. FIGS. 18(a) and 18(b) are graphsshowing profiles of X-ray intensity measured along lines (a) and (b) inFIG. 17. Specifically, FIG. 18(a) shows a 6^(th) X-ray intensity profileof the reflection image counted from the upper side; and 18(b) shows anintensity profile of the reflection image for the column extending fromthe upper end to the lower end thereof. The distance between ZnO thinfilms corresponding to respective stripe-shaped pixels is 0.8 mm, andthe width of each stripe is about 0.5 mm. This confirms that theinter-pixel resolution in the present invention is not greater than 0.5mm. Next will be described the case of a 001 sapphire substrate testedin a third test example of the present invention.

FIG. 19 shows a 006 reflective image of a sapphire substrate; and FIG.20 shows a profile of X-ray intensity measured along line A—A in FIG.19. The image of FIG. 19 confirms that the substrate is a uniformmonocrystal having no twist.

FIG. 21 shows profiles obtained through measurement in which thethickness of ZnO film was measured on a cell-by-cell basis by use of athickness gauge. A stylus-type thickness meter [Dektak³ST Surfaceprofiler (product name), Model 173003-R, product of Solan TechnologyDivision) was used as the thickness gauge. Notably, the profiles of FIG.21 do not correspond to the image shown in FIG. 17.

When the profiles of FIG. 21 are compared with the ZnO 002 reflectionimage, we find correspondence. That is, the thickness of ZnO thin filmcan be measured at high speed through X-ray diffraction measurement.

FIG. 18(a) shows the X-ray intensity profile of the 6^(th) cell (countedfrom the upper side) of the ZnO thin film, which was recorded on thetwo-dimensional detector and is shown in FIG. 17. In other words, FIG.17 has information of 12 X-ray intensity profiles. Further, throughrepeated operation of shifting the samples in the X direction by use ofthe sample stage 9 and measuring the diffraction profile of a differentcolumn, the profiles shown in FIG. 18(a) are obtained within a fewminutes. In an exemplary case in which the number of columns is 10, 120(12×10) profiles as shown in FIG. 18(a) are obtained. Needless to say,all the profiles may be stored in the memory unit 23 shown in FIG. 7.However, since the number (120) of profiles is very large, a researcherrequires a very long time to display and view the profiles.

Therefore, provision of the function for automatically sorting out dataand for storing or displaying only a peak position, a peak intensity,and a peak half-value width is very advantageous, from the viewpoint ofreduction of data and extraction of necessary data only.

Since the peak position includes information regarding lattice constantsof the thin film sample, only the lattice constants of the respectivepixels can be stored in the form of a table.

Also, since the peak intensity includes information regarding thethickness of the thin film sample as described, the film thicknesses ofthe respective pixels can be stored in the form of a table.

Moreover, since the peak half-value width includes information regardingthe crystallinity of the thin film sample, the result of evaluation asto crystallinity can be stored in the form of a table.

As described above, when combinatorial pixels are evaluated, diffractionprofiles derived from the respective pixels are measured at high speed.In order to efficiently use the diffraction profiles, theabove-described information useful for evaluation of a thin filmmaterial must be extracted and sorted out. However, since the amount ofinformation is extremely large, performing such operation manually on apixel-by-pixel basis is inefficient, and such operation must beautomated.

FIG. 22 is a schematic view of an X-ray diffraction apparatus showingthe case in which a point light source is used, and FIG. 23 is aschematic view of an X-ray diffraction apparatus showing the case inwhich a line light source is used. The views of FIGS. 22 and 23 are froma horizontal direction.

When a point light source 31 is used, as shown in FIG. 22, a lightsource of high brightness can be used as the light source 31. Althoughthe structure of the apparatus becomes simple, measurement cannot beperformed properly if a crystal involves disorder in its tilt. Further,when the Bragg angle increases, influence of longitudinal divergence ofX-rays becomes impossible to ignore. In FIG. 22, reference numeral 32denotes a monochromator having a curved crystal; 33 denotes a slit; 34denotes a sample; 35 denotes a (ω/2θ) goniometer; and 36 denotes atwo-dimensional detector.

When a line light source 41 is used, as shown in FIG. 23, a properSoller slit 46 must be provided in order to guarantee that only an X-raydiffracted at a certain point of the curved crystal reaches apredetermined point on a two-dimensional detector 47. In FIG. 23,reference numeral 42 denotes a monochromator having a curved crystal; 44denotes a sample; and 45 denotes a (ω/2θ) goniometer.

The X-ray diffraction apparatus of the present invention can beconfigured such that measurement of samples can be performed by use ofeither the point light source or the line light source.

The above-described apparatus configuration enables a huge amount ofdata to be measured within a short period of time.

The present invention is not limited to the above-described embodiment.Numerous modifications and variations of the present invention arepossible in light of the spirit of the present invention, and they arenot excluded from the scope of the present invention.

As have been described in detail, the present invention provides thefollowing advantageous effects.

(1) X-rays from an X-ray source can be utilized most efficiently, and aplurality of samples disposed in a matrix pattern can be measured on acolumn-by-column basis. In particular, simultaneous measurement of aplurality of samples in the same column enables precise measurement ofslight variations among the plurality of samples.

(2) Combinatorial samples can be evaluated accurately at high speedthrough X-ray diffraction analysis.

INDUSTRIAL APPLICABILITY

The combinatorial X-ray diffraction apparatus of the present inventionis preferably used as an apparatus for evaluating epitaxial thin film,because the combinatorial X-ray diffraction apparatus of the presentinvention can perform, at high speed, a precise, column-by-columnmeasurement of a plurality of samples disposed in a matrix pattern,through X-ray diffraction.

What is claimed is:
 1. A combinatorial X-ray diffraction apparatus forexamination of plural samples arranged in a matrix of linear arrays asrows and columns, said apparatus comprising: (a) an X-ray source forradiating X-rays from a point-shaped focal point; (b) a curvedmonochromator which spectrally reflects the X-rays radiated from theX-ray source; (c) a first slit disposed for restricting radiation of thereflected X-rays to a measurement area; (d) a holder for holding,arranged in the matrix, the plural samples to be irradiated with theX-rays; (e) a knife-edge disposed relative to said holder to define aknife-edge slit therebetween further restricting the X-ray irradiation,having passed through said first slit, to a single linear array of saidsamples; (f) a two-dimensional detector for receiving diffraction X-raysreflected from at least one of the samples held by the holder; (g) agoniometer having a ω-axis shaft and a 2θ-axis shaft, the holder beingmounted on the ω-axis shaft, and the two-dimensional detector beingmounted on the 2θ-axis shaft; (h) a drive unit for moving the positionat which the X-rays impinge the samples; (i) an information processingapparatus for fetching output data from the two-dimensional detector andprocessing the data; and (j) a display unit for displaying the result ofprocessing performed in the information processing apparatus.
 2. Acombinatorial X-ray diffraction apparatus for examination of pluralsamples arranged in a matrix of linear arrays as rows and columns, saidapparatus comprising: (a) an X-ray source for radiating X-rays from aline-shaped focal point; (b) a curved monochromator which reflects theX-rays radiated from the X-ray source, while converting the X-rays tomonochromic rays; (c) a slit disposed for restricting radiation of thereflected X-rays to a measurement area; (d) a holder for holding,arranged in the matrix, the plural samples to be irradiated with theX-rays; (e) a knife-edge disposed relative to said holder to define aknife-edge slit therebetween further restricting the X-ray irradiation,having passed through said first slit, to a single linear array of saidsamples; (f) a Soller slit which affects the X-rays having passedthrough the knife-edge slit; (g) a two-dimensional detector forreceiving diffraction X-rays reflected from at least one of the samplesheld by the holder; (h) a goniometer having a ω-axis shaft and a 2θ-axisshaft, the holder being mounted on the ω-axis shaft, and thetwo-dimensional detector being mounted on the 2θ-axis shaft; (i) a driveunit for moving the position at which the X-rays impinge the samples;(j) an information processing apparatus for fetching output data fromthe two-dimensional detector and processing the data; and (k) a displayunit for displaying the result of processing performed in theinformation processing apparatus.
 3. A combinatorial X-ray diffractionapparatus according to claim 1 or 2, wherein said two-dimensionaldetector has a plurality of pixels, wherein diffraction X-raysdiffracted at a linear array including at least two samples, arereceived simultaneously by the two-dimensional detector; whereinpositions of each sample in a direction of diffraction angle θ and in adirection perpendicular thereto are measured; and diffraction X-rayintensities of pixels of the two-dimensional detector corresponding toeach sample are integrated by said information processing apparatus inorder to individually obtain the intensity of diffraction X-rays fromeach sample.
 4. A combinatorial X-ray diffraction apparatus according toclaim 3, wherein from diffraction X-rays diffracted at a linear arrayincluding at least two samples, the intensity of a diffraction X-rayfrom each sample is separated and related with angle informationrepresenting a diffraction angle θ, through movement of the sample onthe goniometer and the movement of the two-dimensional detector, withina desired angle range.
 5. A combinatorial X-ray diffraction apparatusaccording to claim 1 or 2, wherein the two-dimensional detector isdisposed such that the two-dimensional detector can receivesimultaneously X-rays from at least two samples forming said singlelinear array.
 6. A combinatorial X-ray diffraction apparatus accordingto claim 1 or 2, wherein the single linear array includes at least twosamples which sequentially satisfy diffraction conditions, and whereinthe two-dimensional detector is disposed to receive diffraction X-raysdiffracted at the linear arrays sequentially.
 7. A combinatorial X-raydiffraction apparatus according to claim 1 or 2, wherein saidinformation processing apparatus normalizes spatial distribution ofX-ray intensity and spatial distribution of sensitivity of thetwo-dimensional detector; wherein said two-dimensional detectorseparately collects pixels or blocks of pixels of diffracted X-rays andfor each pixel or each block of pixels of diffracted X-rays collectedtwo-dimensionally, X-ray intensity correction is performed by saidinformation processing apparatus according to the position thereof.
 8. Acombinatorial X-ray diffraction apparatus according to claim 1 or 2,wherein said holder is mounted for movement relative to the goniometer,wherein from diffraction X-rays diffracted at a linear array includingat least two samples, the intensity of a diffraction X-ray from eachsample is separated and related with angle information representing adiffraction angle θ, through movement of the sample on the goniometerand the movement of the two-dimensional detector, within a desired anglerange.
 9. A combinatorial X-ray diffraction apparatus according to claim5, wherein from diffraction X-rays diffracted at a linear arrayincluding at least two samples, the intensity of a diffraction X-rayfrom each sample is separated and related with angle informationrepresenting a diffraction angle θ, through movement of the sample onthe goniometer and the movement of the two-dimensional detector, withina desired angle range.
 10. A combinatorial X-ray diffraction apparatusaccording to claim 5, wherein said two-dimensional detector has aplurality of pixels, wherein diffraction X-rays diffracted at a lineararray including at least two samples, are received simultaneously by thetwo-dimensional detector; wherein positions of each sample in adirection of diffraction angle θ and in a direction perpendicularthereto are measured; and diffraction X-ray intensities of pixels of thetwo-dimensional detector corresponding to each sample are integrated bysaid information processing apparatus in order to individually obtainthe intensity of diffraction X-rays from each sample.
 11. Acombinatorial X-ray diffraction apparatus according to claim 5, whereinsaid information processing apparatus normalizes spatial distribution ofX-ray intensity and spatial distribution of sensitivity of thetwo-dimensional detector; wherein said two-dimensional detectorseparately collects pixels or blocks of pixels of diffracted X-rays andfor each pixel or each block of pixels of diffracted X-rays collectedtwo-dimensionally, X-ray intensity correction is performed by saidinformation processing apparatus according to the position thereof. 12.A combinatorial X-ray diffraction apparatus according to claim 6,wherein said two-dimensional detector has a plurality of pixels, whereindiffraction X-rays diffracted at a linear array including at least twosamples, are received simultaneously by the two-dimensional detector;wherein positions of each sample in a direction of diffraction angle θand in a direction perpendicular thereto are measured; and diffractionX-ray intensities of pixels of the two-dimensional detectorcorresponding to each sample are integrated by said informationprocessing apparatus in order to individually obtain the intensity ofdiffraction X-rays from each sample.
 13. A combinatorial X-raydiffraction apparatus according to claim 6, wherein said informationprocessing apparatus normalizes spatial distribution of X-ray intensityand spatial distribution of sensitivity of the two-dimensional detector;wherein said two-dimensional detector separately collects pixels orblocks of pixels of diffracted X-rays and for each pixel or each blockof pixels of diffracted X-rays collected two-dimensionally, X-rayintensity correction is performed by said information processingapparatus according to the position thereof.
 14. A combinatorial X-raydiffraction apparatus according to claim 6, wherein from diffractionX-rays diffracted at a linear array including at least two samples, theintensity of a diffraction X-ray from each sample is separated andrelated with angle information representing a diffraction angle θ,through movement of the sample on the goniometer and the movement of thetwo-dimensional detector, within a desired angle range.
 15. Acombinatorial X-ray diffraction apparatus according to claim 7, whereinsaid two-dimensional detector has a plurality of pixels, whereindiffraction X-rays diffracted at a linear array including at least twosamples, are received simultaneously by the two-dimensional detector;wherein positions of each sample in a direction of diffraction angle θand in a direction perpendicular thereto are measured; and diffractionX-ray intensities of pixels of the two-dimensional detectorcorresponding to each sample are integrated by said informationprocessing apparatus in order to individually obtain the intensity ofdiffraction X-rays from each sample.
 16. A combinatorial X-raydiffraction apparatus according to claim 7, wherein from diffractionX-rays diffracted at a linear array including at least two samples, theintensity of a diffraction X-ray from each sample is separated andrelated with angle information representing a diffraction angle θ,through movement of the sample on the goniometer and the movement of thetwo-dimensional detector, within a desired angle range.